In recent years, rail transit in China has been developed rapidly. It provides people a fast and reliable way to travel. However, a problem of vibration and noise generated by the rail transit seriously affects life quality of surrounding residents, and endangers safety of surrounding buildings, and has an impact on the stability, safety and service life of rail.
Researches show that in noise generated by operating of trains, wheel-rail noise accounts for a significant proportion, in which mid-frequency and high-frequency noise radiated by vibration of steel rails contributes a considerate portion to finally overall noise. For this reason, vibration and noise management of steel rails is of great significance to vibration and noise reducing for urban rail transit. In order to control the vibration and noise of the steel rail, engineers have developed a variety of vibration and noise attenuating products, among which a tuned vibration damper is a common one. The tuned vibration damper, as a tuned vibration damper disclosed in Patent Application No. 200480019707.1, utilizes a tuned device consisting of a mass-spring system to generate work by applying a reactive force to dissipate energy when the steel rails vibrates so as to reduce vibration of the rails. This kind of product can obtain reducing vibration and noise to some extent. Nevertheless, it can be found from engineering application that for an elastic element made of elastic materials, such as rubber, and a internal mass block then disposed in the elastic element are commonly used in existing such technical solutions, physical properties of the elastic materials, such as rubber are susceptible to ambient environment and easily scratched so as to be damaged by external objects after exposure to ambient environment for a long time, which in turn adversely affects vibration and noise reduction performance and service life of the tuned vibration damper, because rail transit spreads widely in various regions where ambient environment conditions are dramatically different. Moreover, since that restraining force imparted to the mass block by the elastic element of rubber kind is less, and that the mass block produces a large pull and push component and a small shear component to the elastic element when the mass block moves within the elastic element, shear energy dissipating cannot be effectively realized and hence vibration attenuating effect is limited. Also, due to structure and material limitations, applicable frequency range of this kind of the tuned vibration damper for rails is relatively narrow. For example, for low frequency control, high elasticity is required for an elastomer, but it makes the elastomer soft and prone to being torn; for high frequency control, high rigidity is required for an elastomer, but it makes the elastomer to have a low elasticity and poor vibration attenuating effect. Furthermore, this kind of tuned vibration damper for rail holds following drawbacks: (1) it is difficult to realize accurate mass turned vibration attenuating in two directions simultaneously since the mass blocks are embedded within the elastic material; (2) for it is impossible to directly measure or tune working frequency, the tuned vibration damper is semi-finished product when being sold and is not matched with the steel rail; (3) once the material breaks, a crack will be formed inside and rigidity of the elastic element and working frequency of the tuned vibration damper will be changed; (4) all parameters cannot be optimized when the elastic element, the elastic material and adhesive material are assembled together; (5) once the elastic material breaks, TMD mass block would fall off, which brings trains hidden safety problems.
To summarize, existing tuned vibration dampers have drawbacks such as limited vibration and noise attenuating effects, unstable properties, narrowly applicable frequency ranges and short service life.